From e6cb593b755645b2d0ae0acd41fd85b41fc7fc7d Mon Sep 17 00:00:00 2001
From: Sebastien Andary <sebastien@naturalpad.fr>
Date: Sat, 29 Jan 2022 15:34:07 +0100
Subject: [PATCH] Allow to disable the workaround "unconsumed messages getting
 stuck in the future". Because this workaround is causing MIDI events drops at
 low block size settings.

---
 include/settings.hpp |  1 +
 src/app/MenuBar.cpp  |  3 +++
 src/midi.cpp         | 13 ++++++++-----
 src/settings.cpp     |  7 +++++++
 4 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/include/settings.hpp b/include/settings.hpp
index 2b7c1a9b..c53f48ca 100644
--- a/include/settings.hpp
+++ b/include/settings.hpp
@@ -61,6 +61,7 @@ extern float knobLinearSensitivity;
 extern float knobScrollSensitivity;
 extern float sampleRate;
 extern int threadCount;
+extern bool disableDawTimeWarpWorkaround;
 extern bool tooltips;
 extern bool cpuMeter;
 extern bool lockModules;
diff --git a/src/app/MenuBar.cpp b/src/app/MenuBar.cpp
index 8f9ade8c..fd779d19 100644
--- a/src/app/MenuBar.cpp
+++ b/src/app/MenuBar.cpp
@@ -548,6 +548,9 @@ struct EngineButton : MenuButton {
 				));
 			}
 		}));
+		menu->addChild(createCheckMenuItem("Disable DAW time warp workaround", "", 
+			[=]() { return settings::disableDawTimeWarpWorkaround; },
+			[=]() { settings::disableDawTimeWarpWorkaround ^= true; }));
 	}
 };
 
diff --git a/src/midi.cpp b/src/midi.cpp
index 79c9cc0d..f4832c05 100644
--- a/src/midi.cpp
+++ b/src/midi.cpp
@@ -7,6 +7,7 @@
 #include <string.hpp>
 #include <system.hpp>
 #include <context.hpp>
+#include <settings.hpp>
 #include <engine/Engine.hpp>
 
 
@@ -339,11 +340,13 @@ bool InputQueue::tryPop(Message* messageOut, int64_t maxFrame) {
 		return true;
 	}
 
-	// If next MIDI message is too far in the future, clear the queue.
-	// This solves the issue of unconsumed messages getting stuck in the future when a DAW rewinds the engine frame.
-	int futureFrames = 2 * APP->engine->getBlockFrames();
-	if (msg.getFrame() - maxFrame > futureFrames) {
-		internal->queue.clear();
+	if (!rack::settings::disableDawTimeWarpWorkaround) {
+		// If next MIDI message is too far in the future, clear the queue.
+		// This solves the issue of unconsumed messages getting stuck in the future when a DAW rewinds the engine frame.
+		int futureFrames = 2 * APP->engine->getBlockFrames();
+		if (msg.getFrame() - maxFrame > futureFrames) {
+			internal->queue.clear();
+		}
 	}
 	return false;
 }
diff --git a/src/settings.cpp b/src/settings.cpp
index 1fb91691..1a16b87a 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -36,6 +36,7 @@ float knobLinearSensitivity = 0.001f;
 float knobScrollSensitivity = 0.001f;
 float sampleRate = 0;
 int threadCount = 1;
+bool disableDawTimeWarpWorkaround = false;
 bool tooltips = true;
 bool cpuMeter = false;
 bool lockModules = false;
@@ -137,6 +138,8 @@ json_t* toJson() {
 
 	json_object_set_new(rootJ, "threadCount", json_integer(threadCount));
 
+	json_object_set_new(rootJ, "disableDawTimeWarpWorkaround", json_boolean(disableDawTimeWarpWorkaround));
+
 	json_object_set_new(rootJ, "tooltips", json_boolean(tooltips));
 
 	json_object_set_new(rootJ, "cpuMeter", json_boolean(cpuMeter));
@@ -305,6 +308,10 @@ void fromJson(json_t* rootJ) {
 	if (threadCountJ)
 		threadCount = json_integer_value(threadCountJ);
 
+	json_t* disableDawTimeWarpWorkaroundJ = json_object_get(rootJ, "disableDawTimeWarpWorkaround");
+	if (disableDawTimeWarpWorkaroundJ)
+		disableDawTimeWarpWorkaround = json_boolean_value(disableDawTimeWarpWorkaroundJ);
+
 	json_t* tooltipsJ = json_object_get(rootJ, "tooltips");
 	if (tooltipsJ)
 		tooltips = json_boolean_value(tooltipsJ);